Question

What is the chemical formula of magnesium nitride?

• A. $M{g}_3{N}_2$
• B. $N_{2}M{g}_3$
• C. $M{g}_2{N}_3$
• D. $M{g}_4{N}_3$

Answer 1

The correct option is A $M{g}_3{N}_2$

Magnesium nitride consists of magnesium ion and nitride ion i.e. $M{g}^{2+}$ and $N{}^{3-}$, which have a charge of +2 and -3 respectively.
$$\begin{array}{ccc}\text{Symbol}& \text{Mg}& \text{N}\\ \text{Charge}& \text{+2}& \text{-3}\end{array}$$
On cross-multiplication and balancing the charge, we get the formula as $M{g}_3{N}_2$.